Take cooked rice in a bowl and add water.
Cover and let it ferment overnight (8–12 hours) at room temperature.
The next day, lightly mash the rice to create a soupy consistency.
Add salt, chopped onion, and green chili.
Drizzle mustard oil for an authentic flavor.
Mix everything well.
Garnish with fresh coriander leaves.
Serve chilled or at room temperature as a refreshing fermented soup.